Many scientists contend that release of halogen refrigerants into the atmosphere deleteriously affects the ozone layer which surrounds and protects the earth from ultraviolet solar radiation. Recent international discussions and treaties, coupled with related regulations and legislation, have renewed interest in devices for recovery and storage of used refrigerants from refrigeration systems for later purification and reuse or for proper disposal. U.S. Pat. No. 4,261,178, assigned to the assignee hereof, discloses a refrigerant recovery system in which the input of a compressor is coupled through an evaporator and through a manual valve to the refrigeration system from which refrigerant is to be recovered. The compressor output is connected through a condenser to a refrigerant storage container. The condenser and evaporator are combined in a single assembly through which cooling air is circulated by a fan. Content of the storage container is monitored by a scale on which the container is mounted for sensing weight of liquid refrigerant in the container, and by a pressure switch coupled to the fluid conduit between the condenser and the container for sensing vapor pressure within the storage container. A full-container condition sensed at the scale or a high-pressure condition sensed at the pressure switch terminates operation of the compressor motor. A vacuum switch is positioned between the inlet valve and the evaporator for sensing evacuation of refrigerant from the refrigeration system and automatically terminating operation of the compressor motor.
Although the system so disclosed represents a significant advance over previous refrigerant recovery devices, further improvement remains desirable. It is an object of the present invention to provide a refrigerant recovery system of the described character which may be readily transported to a job site, such as a building air conditioning or heat pump system, which may be operated at such job site to evacuate and store used refrigerant for later purification or disposal, and which may be readily physically manipulated and operated by a single relatively unskilled operator. Another object of the invention is to provide a refrigerant recovery system of the described character which is economical to fabricate and assemble, which is reliable over an extended operating life, and in which the various system components are readily accessible for repair or replacement as required. In furtherance of the foregoing objectives, particularly as they relate to portability and size reduction, it is another and more specific object of the invention to provide a combined heat-exchange/oil-separation unit which will vaporize incoming refrigerant fed to the compressor input, liquify refrigerant fed from the compressor output to the storage container and remove oil from the refrigerant, all without requiring auxiliary air circulation or cooling as by a separate fan or the like.
Another object of the present invention is to provide apparatus for purifying recovered refrigerant which is economical, reliable, portable and easy to operate. A further object of the invention is to provide a combined refrigerant recovery and purification apparatus.